The head of Australia’s recovery mission to Ukraine says it is "well placed" to send a contingent of armed and unarmed federal police officers to assist with the investigation of MH17 early next week but indicated defence personnel would not accompany it to the site.

Australian and Dutch officials have been working towards securing a deal to allow officers from both countries to gain access to the site of the MH17 crash in Ukraine.

Retired Air Chief Marshal Angus Houston, who is leading the operation, told ABC’s Insiders on Sunday separatists at the site had been “professional and cooperative” with Australian authorities on earlier visits, and he was hopeful access would be granted soon.

“In terms of when it might happen, I think we are well positioned to go in some time next week, and at this stage there are a couple of things that still have to be negotiated to enable that to happen,” he said.

“So, until we've done that, I would prefer to be a little bit careful in saying it will happen this day or that day.”

The prime minister, Tony Abbott, had earlier announced that a contingency of Australian federal police officers – including armed and unarmed personnel – would attempt to gain access to the site. He also said Australian defence force personnel would be deployed.

“Many of the AFP deployed won’t be armed, some of them could be armed, and yes there will be some ADF as part of this deployment,” Abbott said last week.

But on Sunday Houston reiterated that it was a “police-led mission” that would have a combination of armed and unarmed personnel “if that’s the way the government decides to go”.

Asked to confirm that Australian military personnel would not be sent to the crash site, he said: “That's absolutely correct because one of the important things here is to posture a non-threatening force, a non-threatening force that will go in with civilian specialists in white vehicles who will do the job on the crash site.”

On Saturday an Australian couple whose daughter died in the crash travelled to the scene without any escort, ignoring warnings, Agence France-Presse reported. They said they were fulfilling a promise to their only child that they would be there.

"She was full of life," said Angela Rudhart-Dyczynski of their 25-year-old daughter Fatima, an aerospace engineering student.

Angela and her husband, Jerzy Dyczynski, who wore a T-shirt with the words "Fatima: We Love You", were overcome with emotion as they walked among the wreckage and scorched earth, and laid a large bouquet of flowers on part of the debris.

The foreign minister, Julie Bishop, has negotiated with Ukrainian authorities to allow Australian personnel to gain official access to the site, but the agreement still needs to be ratified by the Ukrainian parliament.

While unarmed police can enter at the invitation of the Ukrainian government "in order to bring in arms, it's in their constitution you have to have parliamentary approval", Bishop told reporters in Eindhoven, Netherlands, on Saturday, AAP reported.

The deal signed with her Ukrainian counterpart, Pavlo Klimkin, still needs to be ratified by the parliament. Getting the arrangement finalised has been complicated by the collapse of the ruling coalition and the resignation of the prime minister, Arseniy Yatsenyuk.

An extraordinary session is scheduled for Thursday, but Bishop and her Dutch counterpart, Frans Timmermans, want the mission approved on Tuesday.

"We want our experts in there as soon as possible," Bishop said. "We want to be able to start retrieving the last of the remains on site as soon as possible and we want the investigation to commence as soon as possible."

Bishop said she and Timmermans would travel to Ukraine on Sunday to meet senior Ukraine officials "to urge them to ratify our respective documents on Tuesday".

"This is a significant request to have a parliament recalled after it went into recession on Friday.

"But last week we were assured that our documents would be ratified on Friday.

"Domestic politics and internal matters intervened so we are returning to ask if it's possible for them to reconvene the parliament on Tuesday because every day that we are not on the site it becomes more contaminated."

The foreign minister said while awaiting ratification Australia and the Dutch could "pre-position and put our resources in place outside Ukraine ready to move as soon as possible".