Some 401(k) plan providers are turning down withdrawal requests from investors.

The Wall Street Journal reported some providers are freezing investments in certain plans and restricting access to certain retirement plan options. This as some employers are finding it difficult to do away with risk investments housed in 401(k) plans. Many funds offered in 401(k) plans lend their portfolio holdings to other investors, receiving in exchange collateral that they invest in normally safe, liquid holdings, according to the May 5 article.

"But in recent months, many of the collateral investments have gone haywire, prompting money managers to restrict retirement plans' withdrawals from the lending funds," the publication reported.

One plan provider has not allowed withdrawals or transfers since last September because of a low performing fund, according to the Wall Street Journal. Retirement plans offered to employees of an energy company have been on lockdown since certain fund holdings had defaulted.

According to the Internal Revenue Service, 401(k) hardship withdrawals are allowed for the purchase of a principal residence, college tuition payments, un-reimbursed medical expenses and funeral expenses among others reasons. The withdrawals are subject to income tax and a 10% penalty is imposed if the recipient is not at least 59 1/2 years of age.