One of the housemates of missing Queensland teenager Pheobe Bishop has been released on bail over weapons charges.

Tanika Kristan Bromley, 33, was arrested on Sunday after police allegedly found a shortened firearm, ammunition, and two replica handguns during a search of a grey Hyundai ix35, along with additional ammunition at a home in Gin Gin, about 50km west of Bundaberg in Queensland.

She has been charged with possessing/acquiring restricted items, unlawful possession of weapons, and two counts of failing to have the required authority to possess explosives.

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Police said the weapons found are not directly linked to the investigation into Pheobe’s disappearance.

Bromley was granted bail on Tuesday following appearances via video link at the Bundaberg Magistrates Court over two consecutive days.

Daily Mail Australia reported that at the time Pheobe was last seen, Bromley was already on bail after appearing in Bundaberg Magistrates Court on March 28 over the weapons charges.

She was also allegedly found with a shotgun and flick knife while on the Capricorn Highway in Emerald, Queensland.

Bromley is scheduled to reappear at Bundaberg Courthouse on June 23 in relation to both matters.

Bromley and her boyfriend James Wood are believed to be the last people to have seen missing teenager Pheobe Bishop before she disappeared on May 15 — a disappearance police are treating as suspicious.

Police believe the couple, who were housemates of the 17-year-old, gave her a lift to Bundaberg Regional Airport in the grey Hyundai owned by Bromley.

Pheobe was reportedly planning to fly to Perth to spend time with her boyfriend but never made it to the terminal.

She was last seen about 8.30am on May 15 on Airport Dr in Bundaberg.

Both the car and the Gin Gin property where the trio lived have been declared crime scenes by police.

The car, with Queensland registration 414 EW3, was seized by police and later released.

According to the Courier Mail, the vehicle was seen in Bundaberg displaying different number plates, replaced with 474 BW8.

In addition to the change, the number plate apparently had NSW written on it. On the car, the Hyundai logo had also been crudely transformed into a Toyota logo.

When asked about the modified number plates, Detective Acting Inspector Ryan Thompson said: “Police are aware of that. We are following up an investigation in relation to that.”

7NEWS.com.au is not suggesting Bromley or boyfriend James Wood are involved in the disappearance of Pheobe. Police have repeatedly said both parties have been co-operative in the investigation.

Police are searching Good Night Scrub National Park, about an hour’s drive from Bundaberg airport, after seizing several items of interest that are undergoing forensic testing.

“We’re conducting an extensive search of that area,” Thompson told reporters in Bundaberg on Tuesday.

Detectives suspect some evidence had been moved from the area after “receiving information” but are still trying to work out what those items may have been.

Police will also be looking at the teen’s heartbreaking social media posts following her disappearance, which indicated she was no longer in contact with her mother.

The teenager had indicated she was “in and out” of home for years.

Her mother, Kylie Johnson, said on Tuesday she was “finding it hard to get out of bed”.

“People have judgements, accusations and continue to say untruths. I’m not going to correct you or be investing what little strength I have to be correcting these statements or people,” she wrote.

“We as a family are just trying to go through the motions of waiting for Phee to come home.”

Pheobe is about 180cm tall with a pale complexion, long hair that has been dyed red and hazel eyes.

She was last seen carrying luggage, wearing a green tank top and grey sweatpants.