The U.S. Securities and Exchange Commission is trying to determine the impact that a plan by the U.S. Department of Labor could have on investors who turn to brokerages for retirement guidance, an official said on Thursday.

The retail brokerage industry has fiercely opposed the Labor Department plan. It would require that financial advisors who give advice to clients about individual retirement accounts (IRAs) and workplace retirement plans such as 401(k)s act as fiduciaries, or in their clients' best interests.

The industry has said that would drive costs up, making IRA advice unaffordable for many investors because Wall Street brokers would not be able to sell the same types of products as they do now.

The U.S. Securities and Exchange Commission staff is giving "technical assistance" to the Labor Department, Stephen Luparello, director of the SEC's Division of Trading and Markets, told the U.S. House Financial Services Committee at a hearing.

Both regulators have been looking at the fiduciary issue for years. The Labor Department, which oversees the regulation of retirement plans, withdrew a previous version of its planned rule in 2012, after fierce industry opposition about costs. It recently delayed its unveiling of a new proposal to early 2015.

Labor Department officials there have said they are concerned about potential conflicts of interest posed by advisers who suggest that clients roll over their workplace retirement plans into IRAs and then earn commissions from trades in those accounts.

The SEC has also been considering whether to revise its adviser conduct rules.

Wall Street, concerned about potential conflicts between the two plans, has been pushing for coordination between the SEC and Labor Department to avoid conflicts between the possible regulations.

"Among other things, the staff is seeking to assess the practical impact potential DOL rulemaking may have on investors who seek to access advice from financial services providers, including broker-dealers," Luparello said in prepared testimony.

Separately, the SEC is considering whether to develop rules that would require Wall Street brokers to act as fiduciaries. Currently, brokers must recommend investments that are "suitable," based on factors such as an investor's risk tolerance and age. Suitable investments, however, may not include those that are the best or most cost-effective for investors, consumer advocates say.