PORTLAND – The owners of the Eastland Park Hotel are asking the city permission to build a ballroom on Congress Square Plaza as part of a multimillion dollar renovation and expansion of  the 85-year-old hotel.

The ballroom would take up nearly all of the park, and advocates for the homeless and many neighborhood residents say the city should focus it efforts on improving the park rather than selling it to a private developer.

But supporters say a ballroom would be an improvement over the little-used park, which is home to loiterers and magnet for litter, and that the proposal would attract more people and investment to the city’s new Arts District.

The project calls for renovating the entire hotel and upgrading it to a four-star hotel affiliated with Westin Hotels & Resorts, an upscale hotel chain, said Gerald Chase of Newcastle Hotels & Resorts, which is managing the hotel and developing the project as part of joint venture with Rockbridge Capital, which is providing most of the money.

Chase said the franchise agreement with Westin Hotels & Resorts has been finalized.

He said the project includes upgrading the Top of the East restaurant and expanding it by about 1,000 square feet, renovating the existing ballroom and building a second ballroom with capacity for 500 people.

When completed next year, he said, the hotel would be able to accommodate conventions of up to 1,000 people, making it the largest convention center in New England outside of Boston.

The developers on Wednesday presented their plans to the city’s Housing & Community Development Committee and later met with the committee in executive session to discuss acquiring the city-owned park.

In the proposal, the ballroom would take up nearly the entire park, leaving a small “passive park” along Congress Street about the width of a driveway.