A Vancouver family faces a choice between spending thousands of dollars or tearing down their tree house because they say the city changed its tune regarding a building permit.

Jayne Seagrave says they were told by the city that the tree house they planned to build for their two sons wouldn't need a permit. But now that it's been completed, the planning department says they do.

Built by Seagrave's husband Andrew Dewberry, an architect, the tree house takes the shape of a pirate ship and wraps around a massive cedar tree in the front yard of the house.

Seagrave told CBC News that she and Dewberry called the city's permit office before construction began and were told a permit wasn't necessary because the tree house was a temporary structure.

At least four city inspectors and engineers visited the tree house, she said, but none of the officials asked that construction be stopped until this week, after the project was finished.

She said she thinks the city changed its mind after getting a complaint from a neighbour.

Seagrave said the city is now telling her a permit was indeed required and that the tree house may have to come down.

"This is considered to be development and therefore becomes something that is subject to an approval process though our development permit process," said Bill Boones, spokesperson for Vancouver's development office.

Seagrave estimates the work needed to get a permit and city approval at this point could cost the family nearly $4,000.

The family has been given 30 days to respond to the city's demands for a permit, she said, adding that they'll use that time to decide what to do next.