By David Thomas

Feb 12 (Reuters) - Former New Jersey Attorney General Matthew Platkin said on Thursday that he has launched a new law firm with other senior lawyers who served with him until he left office last month.

Platkin said the new firm — Platkin LLP — would pursue cases against large companies such as technology firms and gunmakers, continuing the kind of work he did as attorney general.

"We wanted to build a firm that’s built on that spirit of taking on tough fights and winning them," Platkin said.

As attorney general, Platkin frequently joined with his counterparts from other Democrat-led U.S. states to file lawsuits challenging policies enacted by Republican President Donald Trump's administration. Platkin was among those who sued to stop Trump's executive order restricting automatic birthright citizenship, which is provided for under the 14th Amendment of the U.S. Constitution. The U.S. Supreme Court is slated to hear arguments again in the matter in April.

Platkin sued Amazon in October, accusing the company of unlawfully refusing workplace accommodations to warehouse employees who have disabilities or were pregnant and firing some who asked for them. An Amazon spokesperson said the claims were untrue and that the online giant offers employees comprehensive accommodations throughout their pregnancy and after giving birth.

Also in October, the state sued gunmaker Sig Sauer in a bid to stop the company from selling its P320 handguns in New Jersey, alleging it knows the guns can discharge without the trigger being pulled. Sig Sauer in a court filing last month said New Jersey's lawsuit has "no basis in law or fact and must be dismissed."

Joining Platkin at his Newark-based law firm are Angela Cai, Ravi Ramanathan and Aaron Haier. Cai was the executive assistant attorney general while Ramanathan led the office's unit that brought civil lawsuits against gunmakers and gun retailers. Haier served as a senior counsel to the attorney general.

Smaller, so-called boutique law firms have gained momentum during Trump's second term, with several launching last year or growing with hires from large firms or government agencies.

The New Jersey attorney general's position is nominated by the governor and confirmed by the state senate. Platkin was replaced by Jennifer Davenport, who was appointed acting attorney general by Democratic Governor Mikie Sherrill.

(Reporting by David Thomas)