Sir Peter Jackson with Chitty Chitty Bang Bang, an item from his collection, pegged for the movie museum in Wellington. He is understood to still be in talks with the city council about a final agreement.

Taxpayers are being asked to fork out $25 million to help pay for the $165m construction cost of the Wellington convention centre project, which will also house Sir Peter Jackson's movie museum.

The project was first budgeted to cost $134m, then increased to $150m and has now grown to $165m, which council documents say is related to changes to the exterior cladding and building design.

Wellington City Council's draft 10-year plan, which sets out its proposed levels of expenditure, earmarks funds to start trickling into construction from 2019/20 for completion in 2022/23.

STUDIO PACIFIC ARCHITECTURE Wellington's combined movie museum and convention centre was budgeted to cost $134m, then increased to $150m and now looks set to cost $165m.

The project, which was announced in 2015, has been mired in delay and is still in a holding pattern while the council and Jackson finalise an agreement.

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It is understood a number of meetings have been held this year to progress the project, which was left floundering after Jackson's scathing letter to the council in December.

SUPPLIED Wellington City Council long-term plan consultation documents say the increase in costs related to changes to the exterior cladding and building design.

Jackson had concerns the city council was "reneging" on its contract with him.

He was critical of the council, which he believed had been pushing ahead selfishly with the museum, for which he would pay $3m in annual rent.

A representative for Jackson and the movie museum project said there was "nothing new to add" and he had no comment.

STUDIO PACIFIC ARCHITECTURE/SUPPLIED Wellington City Council has asked the Government for $25m of the $165m.

The council referred all questions about the project to Wellington Mayor Justin Lester, who said the council was "working constructively" with stakeholders. He refused to comment further.

However, council's long-term plan consultation documents show the capital construction cost of $165m, included a $25m request for funding from central government.

It is understood the council tried to be "proactive" when it went cap in hand to the previous Government, asking if it would consider funding for Wellington, after financial support was requested for convention facilities in Christchurch and Queenstown.

It is understood the current Government was considering the request, but money would remain in Government coffers until a successful deal was done with Jackson.

The documents show the council would spend about $7.4m a year operating the museum in the first six years it was open, with the contributions dropping slightly in the future.

By 2028, the movie museum and convention centre would add $117m to council debt, even after its $23m in repayments, over the next decade.

The bulk of the project would be funded by commercial and downtown ratepayers, either through the downtown targeted rate or their share of the general rate.

The council expects to use $1m-$2m per year, from the city growth fund, for the first five years, to reduce the impact of this proposal to ratepayers, the documents say.

Taxpayers' Union executive director Jordan Williams said he could understand why Wellington would want some of the cream offered to other cities and believed it was a "hangover" from the previous Government that gave dollops to film and tourism.

"It's difficult to assess when we don't know the proportion of the risk Sir Peter Jackson and co are taking in comparison to ratepayers."

Wellington Chamber of Commerce chief executive John Milford said he supported the "sensible" approach of going to the Government for money.

He was not surprised the cost of construction had increased since the project was announced.

"However, we are still waiting for the final business case to be published [with details] and we can't have that until partnership agreements are completed."

* A previous version of this story said taxpayers were being asked to pay $25 million (of an estimated $165m) towards the Sir Peter Jackson movie museum and a convention centre. This was based on information obtained from the Wellington City Council. The council has since clarified that the $25m requested from the Government would be put towards the cost of the convention centre only – not the movie museum.