Online home-rental marketplace Airbnb announced March 26 it had struck an unprecedented deal with Portland city officials to collect lodging taxes in exchange for legalizing short-term rentals. Even skeptics said it looked like a good compromise.

Those neighborhood association leaders have changed their mind.

The Rose City Park Neighborhood Association on Wednesday sent Portland planning officials a nine-page letter outlining objections to proposed city zoning code amendments which would allow Airbnb rentals.

"My initial read of this amendment," writes Tamara DeRidder, Rose City Park land-use co-chair, "had led me to believe that only home owner primary dwellings could be used for short term rentals—which I found to be false."

Proposed regulations released by the city Bureau of Planning and Sustainability on March 21 would allow rental of up to two bedrooms a night without a $4,130 zoning review—requiring a $147 annual fee instead.

The neighborhood association's objections are numerous.

They say short-term rentals would undermine Neighborhood Watch programs and allow property owners to operate "a commercial motel atmosphere" while living in a mobile home on-site.

But the most forceful complaint is that Airbnb rentals will squeeze the affordable housing market.

"The result of losing longterm rental housing in the inner Single Dwelling neighborhoods," the letter says, "will force… elderly, protected classes, and working poor into areas such as East County, away from services, transit, and walkable neighborhoods."

The letter argues that allowing Airbnb rentals would violate city policy that protects affordable housing, because the change "permits owners to raise rents astronomically, such as from $500/mo. to $500/week."

Bureau of Planning and Sustainability officials could not be immediately reached for comment. A public hearing on the proposed code changes is scheduled for April 22.

Airbnb, a San Francisco online startup valued at $10 billion, is moving into new Old Town headquarters even as city inspectors issue citations to homeowners using the website to rent out guest rooms.