A top Senate Democrat says he regrets not doing enough to fix Obamacare.

Sen. Jon Tester, D-Mont., acknowledged Thursday that mistakes were made with Obamacare and Democrats failed to communicate what was in the bill and did little to make modifications over the past seven years to make it better.

"There were plenty of mistakes made with the Affordable Care Act," Tester told Fox News. "It was a big bill that should have been made better and never happened. I regret not making it better."

Tester cautioned Republicans from being too quick to celebrate a legislative win and urged his Republican colleagues to work across the aisle to either fix the House bill or offer a better Senate version.

"Healthcare has problems. There issues, there's folks that can't afford healthcare under the current system," Tester added. "We out to work to fix that but without throwing out the pre-existing and lifetime caps."

Senate Republicans have so far signaled they do not intend to take up the House-passed healthcare bill but instead plan to offer its own legislation, incorporating elements from the lower chamber.